i did my taxes online and got amount due for both the federal and state taxes but today i found out that there was some miscalulation and i should receive a state refund. so how do i file a amended return and how will i get the refund for the taxes already paid to the state amout due for the wrong calculation earlier.

“i did my taxes online and got amount due for both the federal and state taxes but today i found out that there was some miscalulation and i should receive a state refund. so how do i file a amended return and how will i get the refund for the taxes already paid to the state amout due for the wrong calculation earlier.”---->I guess ,as you said, you do not need to file your federal amended return since you are not subject to refund on your federal return. So, you need to visit Dept of Revenue of your state to check your state refund status and as long as you qualify for a refund; as you can see, a simple math miscalculation on a state tax return will often be corrected by your state tax agency, so there is usually no need to file an amended return. However, if you discovered, for example, that your income is more or less than reported, you should file an amendment to your state tax return. Each state requires a different amendment form.You neeed to obtain a tax amendment form from the state's tax board. This form is often available on your state tax board's(or dept of rec or whatever) website. You should attach any additional forms or documents to the amendment form. For example, you should attach a new W-2 to report additional or loss of income. I guess your state tax amendment has to be filed within 3 years of the date the original tax return was due, or within two years of the date you paid the tax, whichever is later. If you owe taxes, you should file an amended return even if 3 years have passed. Like the IRS, your state may also use a special form for an amended return. Many states also use the X suffix for the form number. For example, CAuses Form 540X. Other states do not. The Hawaii form, for example, is Schedule AMD.Don't forget to attach a copy of your amended federal return (Form 1040) to your amended state return, if the state requires it, as is usually the case. Refunds are forfeit after 3 years, but tax debts remain until they are paid.ALSO, your state tax amendment must be filed by mail.